I m trying to replace my old 3way switch with new one, Zooz Z-Wave Plus On Off Wall Switch ZEN21 (White) VER. 2.0

Here is how my wiring looks, the color of the wires is wrong(my guess as traveller should be red):

enter image description here

That's why assumed what every wire is. This is how the other side of the 3way looks like :

enter image description here

I don't have the photo of the switch I m trying to replace but it looked exactly like the opposite side switch. Neutral was connected on one side, and line and load on the other. Assuming I was correct that white wire is Neutral.

This is the back of my new switch :

enter image description here

This is how I wired it now, put traveler in traveler, and neutral in neutral, as well as line and load on the other side. Again this is assuming my assumptions were correct in the first image :

enter image description here

I hope it does not matter in which hole I put the wires in, upper or lower ones on the backside of my new switch. As every type(neutral, traveler, line and load) has 2 holes to put the wire in

The LED light on the new switch turns on when the other side of the switch is turned off, indicating that something is not wired right :

enter image description here

Also turn on/off on the new switch does nothing. What am I doing wrong here? What can I try to wire this right. I mean the old simple switch worked just fine, did I buy something I can't really use on its own, or I messed up the wiring?

Edit 1: The old switch did not make use of the 'traveler' wire, and it worked. Again provided that my guess about traveler wire is actually accurate in image 1.

Edit 2:

The light is now constantly on in this scenario, and I can turn it off and on from the other switch (black wires are touching). That would probably mean one of the black ones is traveler wire right? I think I m really close here, any ideas?

enter image description here

Edit 3:

Since Harper pointed to me earlier in comments guessing isn't productive. So I watched this short video to figure out configuration of my switches, there are two. I managed to have these both switches working after watching the video using 'old' switches :

1) Switch A with hot wire, and two travelers. I used exact same steps as explained in video. I do not have any red wires like in video, but person in the video said 'once you disconnect both switches and you find a switch where there is house current, thats a hot one, others are travelers' 2) Switch B(I m trying to replace this switch) with load wire, and two travelers. This is my current setup :

enter image description here

Two travelers into two traveler sockets, neutral from the wall into neutral, load into load. I really don't get why is this working especially because I managed to get the old switch to old switch re-wired and working. Its just how to 'map' existing working wire configuration into this new fancy switch with different labels. For example there is no socket called common, here is a photo again:


  • super doubt this is 3-ways the way you are discussing, because they require /3 cable which means there would be red wires in your bundles. These are all /2. Your attempts to assign functions to the wires seem loke wild guesses to me, that is not constructive. Yes normally red wires are involved because 3-way circuits require /3 cable (now /4). Where does power go to first? The lamp? Oct 17, 2017 at 16:12
  • @Harper you're right, it may not be a 3way, but also maybe the old house wiring. I've seen a power being white wire in my garage for instance. Yes the power goes to the lamp first. What do I do? I have all equipment on me. Like meter and the currency testers etc
    – ant
    Oct 17, 2017 at 16:37
  • @Harper also check out my second question edit and photo
    – ant
    Oct 17, 2017 at 16:47
  • Are there two cables going into the remote switch (picture 2)? Oct 17, 2017 at 17:10
  • @Harper I added one more update
    – ant
    Oct 17, 2017 at 18:32

2 Answers 2


I think your wiring situation looks like this

enter image description here

I believe it is a 3-way circuit, and the lack of any red wires, indicates the person used a cheat: using two 14/2 cables paired when he should have used 14/3 (with the red wire). So this accounts for two cables in both boxes. This leaves only one cable in the "smart switch" box. With only one cable remaining, that can only go to the lamp, meaning power is coming into the lamp, not the switch. The entire 3-way complex is a switch loop.

Since all your wires are black and white, I took the liberty of adding tape to color-code the actual functions. Where a wire is taped, think like the tape color is now the wire color. Now in any of these cables, it may be used the other way around, e.g. white for switched hot. In the 2-cable segment, any wire can be any of the functions. I am guessing.

I use yellow for both messengers because they both do the same thing, are both interchangeable (you can swap them and it won't do any harm). However they are not the same, landing both messengers on one screw terminal will not work.

Note that in the first (right) switch box, there is always-hot and switched-hot.
There is no neutral in a switch loop. Ergo you will not have much luck making that smart-switch work.

  • you were spot on, that's why it was so difficult to wire it for me. Not that it would be easier with regular setup, cause I m not electrician or even electric savvy person, but I do enjoy to learn. As soon as I 'figured out' (was really a lot of youtube) that the smart switch needs neutral, and this time I took meter to verify which wire is which. it worked great at the end. thanks
    – ant
    Oct 18, 2017 at 15:21

This is your wiring diagram enter image description here

You're going to be connecting both the line side and load side from your new switch so you may need to find one of those in the existing 3 way. Your existing 3 way only requires two conductors one traveler and a neutral connected to the common terminal to make the Z-wave work. Apparently it senses continuity between the neutral and traveler and that tells your Z-wave which condition you are calling for from the existing. So your existing 3 way is not really a power switch at this point. It's only a digital control point.

You just need to connect up as the Z-wave as it is clearly labeled.

Hope this helps.

  • hi @Retired Master Electrician please take a look at my update 3. I had re-wired and got this working with old switches, but since this new one has different labels I m confused where to put which wire.
    – ant
    Oct 17, 2017 at 18:23
  • I really admire through your pictures and attached video's and your edits to help describe your problem, and believe me I am not trying to sound contemptuous. You need to grasp the concept of how the Z-wave and the remaining 3 way interact. You're not connecting up two 3 ways. You're actually connecting up a control loop and reconfiguring the power to work on the Z-wave (the controller). Now I have looked at the image link you posted on Edit 3 and the back of the Z-wave is labeled exactly like the image I posted. Oct 17, 2017 at 20:09
  • You will need three wires going between the two switches. One will become either the switch leg (load side) or the line side. The next you need to mark as the Traveller whether it's red or not. The last you need to mark neutral you need to wrap it with white tape inside both boxes or if one the travellers is white, use it as a neutral. Now connect them up just as the image shows. If you're still struggling with the concept, you probably need a professional to come to your dwelling and have them walk it through with you. Oct 17, 2017 at 20:16
  • I have no understanding of electric circuits and schematics what so ever. But I felt like if there was something in place I could make it work, easier said than done. With that said I made it work. I ll describe it in an answer, just too tired now. Thanks for trying to help though
    – ant
    Oct 17, 2017 at 20:16

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